Circuit interrupter



06L 1932- G. L. BossARD 1,880,740

CIRCUIT INTERRUPTER Filed May I51, 1929 Patented Oct. 4, 1 932 UNITED STATES PATENT OFFICE exsnnnr L. BOSSARD, or DAYTON, onro, AssIeNoa, IBY mnsnnassrenmnnrs, TO'THE LELAND ELECTRIC COMPANY, or DAYTON, 01110, A CORPORATION or 01110 7 CIRCUIT mrnxnnrrnn- App11qation ii1ed ay a1, 1929. Serial No. 367,515..

This invention relates to circuit interrupters of the mercury tube type.

One object of the invention is the provislon of a circuit interrupter of the mercury tube type having a depending cup portion through which an electrode enters the tube, the cup portion having a metal enclosure in heat absorbing and dissipating relationship therewith.

Another object of the invention is the provision of a mercury tube circuit interrupter having electrodes formed of a series of spaced conductors embedded in glass and spaced from one another by glass.

Still another object of the invention is the provision of a mercury tube circuit interrupter having a tubular body portlon provided with a series of spaced dependlng cup portions each adapted to retain a small portion of the mercury to provide for mercury to mercury contact within the tube, the cup portions being arran ed so as to provide for effective circuit ma ing and breaking at comparatively high speeds of oscillation.

Further ob ects and advantages of the 1nvention will be apparent from the following description and from the accompanying drawing in which i Fig. 1 is a side elevation of a mercury tube embodying the present invention;

Fig. 2 is a view correspondingto Fig. 1 but showing the tube in a tilted posltion;

Fig. 3 is an enlarged central section through the mercury tube shown in Fig. 1;

Fig. 4 is an enlarged section on the line 4-4 of Fig. 3; and y Fig. 5 is a side elevation of a modified form of tube construction.

Referring to the drawing by reference numerals 10 designates a circuit making and breaking device of the mercury tube type that is, one having a body part 11 0f glass or other suitable insulating material, which is provided with a plurality of electrodes and contains a quantity of electrical conducting liquid such as mercury, as indicated at 12. The mercury is adapted when the tube is oscillated to bridge the space between adjacent electrodes and to interrupt the circuit periodically. As shown in Fig. 1 the tube may be nitrogen or a mixture of nitrogen and other inert gasesunder very low pressure, the gas contents of thetube being evacuated at the time the tube is sealed, and the mercury is thus prevented from oxidizing and is maintained for long periods of time-in the chemically pure state in which it is first introduced into the tube. The tube is provided with a plurality of depending well or cup portions where the various electrodes enter. As shown in Figs. 1 and 3 the tube has three such cup portions indicated at 18, 19 and 20. The two cup portions 18 and 20 are near opposite ends of the tube and the cup portion 19 is near the middle and equally spaced from the two cup portions 18 and 20, and each of thesecup portions is so shaped that a small portion 21 of mercury is retained therein when the main portion of the mercury has moved away. This small portion 21 is always maintained in electrlcal connection with the contact surface 22 of the correspondingelectrode and a mercury to mercury contact'is thus provided so there is never any tendency for oxidation or sparking at the contact surface ofv the electrode.

Each electrode preferably comprises a series of spaced apart wires or conductors 23 as.

indicated in Fig. 4, several of such conductors being shown. These various conductors are sealed in the glass of the cup portion and a portion of this glass separates one wire-23 from another. These wires often have to carry comparatively large currents and are c 96 therefore likely to become quite hot, but by separating the individual wires from one anotherthe heating effect of the currents they carry does; not tend to cause such expansion of the material as to interfere with the airtight seal of the wires. Preferably these wires are of platinum and their upper ends extend slightly beyond the top of the glass in which they are sead'ed so that good contact can be made with: the mercury portion which is maintained in the cup under allconditions of normal operation.

Enclosing each cup portion is metal part 25, shown in the form of a thimble. This onclosure 25 is of some good heat conducting material such as brass, and it is cemented or otherwise securely attached to the glass cup portions so as to provide the needed mechanical strength at this portion of the tube, and provide for heat dissipation. The metal enclosure'25 is provided in heat absorbing relationship with the cup portion of the tube and its electrode; and as it is freely exposed to the air the heat may be rapidly dissipated from the surface of the enclosure 25,'and thus minimize the possibility of leakage or breaking of the seal where the electrode passes into the cup portion. i

As shown in Figs. 1 and 3, the body portion 11 of the tube is curved in the direction of its length and the degree of curvature 'is so coordinated with the amount of mercury-in the tube and the distance between adjacent cup portions that the mercury will not bridge the space betweenthree electrodes at the same time. This curvature is present at the bottom of the tube between the well or cup portions, and thus as shown in Fig. 3 when the tube is horizontal the main portion' 12 of the mercury will not contactwith either the portion 21 in the cup portion 18 or the mercury in the cup portion 20 but is just ready to make contact with either as soon as the tube is tilted a very slight amount from its horizontal position. This is true when the tube is stationary and it is also true when the tube is in motion so it is impossible for the mercury to connect the mercury in both cups 18 and 20 at the same time. A small angular tilt of the tube from the position shown in Fig. 3 will cause a circuit to be made from the lead wire 27 to thelead wire 28 or 29 connected to the electrodes and these wires of course may be connected to any electrical circuit to be controlled the lead wire 27 usually being connected to a source of power while the lead wires 28 and 29 are connected to the loads to be energized. As the cup 19 is equallyspaced from the end cups, as shown, the angular tilt from a horizontal position required to close the circuit connected to either the wire 28 or 29 will be the same and both circuits will be energized similar lengths of time when the tube is oscillated back and forth in a regular manner. The tube curvature is particularly desirable for mercury tubes adapted to oscillate back and forth at comparatively high speeds, as a considerable amountof mercury can be used in the tube. and in traveling from one end of the tube to the other it does not tend to completely pass or flow over the metal well or cup, Operat ng speeds well in excess of 200 oscillations per minute have been satisfactorily obtainedin operationover long periods of time. At such high speeds the movement of the/tube is so fast that the mercury tends to remain generally in the center of the tube without muchactual bodily movement or flow with respect to the cup portions of the tube 10. The cup portion 31 is adjacent one end of the tube and the portion 32 is near the center so that the mercury can either bridge the space between the two cups, or run down to the end 33 of the tube and interrupt the flow of current between the two lead wires 34; and 35.

While the forms of apparatus herein described constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise forms of apparatus, and that changes may be made therein without departing from the scope of the invention which is defined in the appended claims.

What is claimed is:

1. A circuit interrupter comprising a hermetically sealed tube of insulating material having a body part provided with a plurality of depending cup portions, a quantity of mercury within said body part, electrodes extending through and sealed in said cup portions, and an insulated terminal wire electrically connected to each of said electrodes, and a metal sleeve fixed to each cup portion the lower ends of the metal sleeves gripping the ends 6f the insulation of said insulated wires.

2 A circuit interrupter comprising a hermetically sealed glass tube having a body part provided with aplurality of depending glass cup portions, a quantity of mercury within said body part, electrodes extending through and sealed in said cup portions, an insulated terminal wire'electrically connected to each of said electrodes adjacent the ends of said cup portions, and a hard sleeve fixed to and enclosing and strengthening each glass cup portion, the lower ends of the sleeves being of reduced size so as to grip the ends of the insulationof said insulated wires.

In testimony whereof I hereto afiix my signature. I

" GISBERT L. BOSSARD. 

